One knows that diamond tipped cutting wheels or other wheels using expensive abrasives such as boron nitride, for example, and which are used for cutting various materials such as asbestos-cement, for example, are formed with a notched metal core, on the periphery of which one deposits electrolytically between the notches, or to which one adds by brazing tips or teeth of sintered metal, containing a diamond base or other expensive abrasive material, to form the cutting elements.
In practice, it has been established that the presence of the notches, designed to allow easier removal of the particles detached by cutting such materials by means of the wheels, causes a very disagreeable hissing or whistling, whose level must be kept below certain fixed limits set by government agencies such as those of the French Labor Inspection and/or Labor Health Board.